[ ghc-Bugs-1358718 ] undefined behavior in time_str (RtsUtils.c)

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Bugs item #1358718, was opened at 2005-11-16 22:34
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Category: Runtime System
Group: 6.4.1
Status: Open
Resolution: None
Priority: 5
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Nobody/Anonymous (nobody)
Summary: undefined behavior in time_str (RtsUtils.c)

Initial Comment:
code looks like this:

char *
time_str(void)
{
    static time_t now = 0;
    static char nowstr[26];

    if (now == 0) {
	time(&now);
	strcpy(nowstr, ctime(&now));
	strcpy(nowstr+16,nowstr+19); /* this is undefined
behavior as buffers overlap, probably 
will show undesired effects if compiler utilise
 copy optimisations */
	nowstr[21] = '\0';
    }
    return nowstr;
}

corrected should look like this:

char *
time_str(void)
{
    static time_t now = 0;
    static char nowstr[26];

    if (now == 0) {
	time(&now);
/* 	ctime_r(&now,nowstr); this is better if available */
        strcpy(nowstr,ctime(&now));
	memmove(nowstr+16,nowstr+19,7);
 }
    return nowstr;
}

--
bmaxa at eunet.yu , Branimir Maksimovic


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